1. Field of the Invention
The present invention relates generally to modular connectors, particularly to a modular connector with electromagnetic interference protection.
2. Description of the Prior Art
Recently, there is an increasing demand for electrical connectors with electromagnetic interference (EMI) protection. Japanese Pat. Kokai No. 59-198,675 ("'675 patent") and U.S. Pat. Nos. 4,569,566 ("'566 patent") and 4,457,575 ("'575 patent") disclose electrical connectors of this type. The '575 patent discloses a modular connector jack having a metal case for covering an insulating housing to prevent leakage of electromagnatic waves. The metal case of this modular connector jack has an integral contact tongue for contact with the metal case of a mating modular connector plug. The entire metal case is made of brass. The electrical connector plug of the '675 patent has a pair of metal case sections and a metal tube to provide an electromagnetic wave shield. The electrical connector plug of the '566 patent has a metal case mounted on the rear end of an insulating housing of contacts to provide an electromagnetic wave shield and an insulating case mounted on the rear end of the metal case.
Since the entire metal case of a modular connector jack of the '575 patent is made of brass, it is very difficult to give the contact tongue a spring property. As a result, the contact tongue can be broken after repeated plug in and off operations. If the entire metal case is made of a conductive material with a spring property in attempt to solve such a problem, it results in poor workability and the increased unit manufacturing cost. The electromagnetic wave shield of an electrical connector plug of the '675 patent consists of three components; two metal case sections and one metal base, requiring many steps of processing a harness and increasing the component cost and thus the unit manufacturing cost. The integral metal case of an electrical connector plug of the '566 patent is formed by drawing, making the processing cost high. In addition, there is a tendency to provide too much play between the insulating case and the rear portion of the metal case.